Safe Shutdown, Relay DIN Mount

SAFE SHUTDOWN CIRCUIT

Add “Shutdown” Macro to Klipper printer.cfg

[output_pin PS_ON]
pin: PE11
value: 1

[gcode_macro POWER_OFF]
gcode:SET_PIN PIN=PS_ON VALUE=0

Add GPIO functions to RPI; sudo nano /boot/firmware/config.txt (or sudo nano /boot/config.txt)
dtoverlay=gpio-poweroff,gpiopin=26,active_low=1
dtoverlay=gpio-shutdown,gpio_pin=17,active_low=1,gpio_pull=up=gpio-shutdown

Set timer relay to “F4” 25 seconds.

OPERATION / LOGIC

Front panel momentary push button switch, provides 5vdc from Mains Relay to the Timer Relay which starts the supply of power for 25 seconds.

RPI boots, and closes the Hi/Lo Relay which is connected to the Mains Relay, which latches the power “ON” while the RPI is booted. The 25 second timer allows for rebooting of the RPI by ssh.

Second Hi/Lo Relay provides a safe shutdown of the RPI. PE11 provides 3.3v to the second relay and opens the GPIO 17 connection to ground. The “Power_OFF” macro allows the relay to close, RPI starts safe